As is well known in the gas turbine engine technology, because of the advent of high speed, high performance and thrust vectoring engines for military use, the goal of the designer is to assure that the engine performance is maintained at a high efficiency level, the weight of the engine and its component parts are held to a minimum and the of different concepts for converting the gas turbine engine utilizing today's technology to perform short and vertical take-offs and landings (STOVL). For example, the Harrier aircraft which has short takeoff and vertical lift capabilities has been in service for several years. However, none of these structures or systems function with the separation of the core and fan flow when in the STOVL mode of operation.
For example U.S. Pat. No. 5,098,022 granted to Thayer on Mar. 24, 1992 and entitled "Flow Diverting Nozzle For A Gas Turbine Engine" discloses a gas turbine engine vertical thrust nozzles that diverts the engine's core stream to provide vertical or a combination of vertical and forward thrust. This mechanism is located in the up stream end of the afterburner.
U.S. Pat. No. 5,082,209 granted to Keyser on Jan. 21, 1992 entitled "Thrust Reverser Assembly" relates to a rotating drum type of configuration to divert the core stream to obtain thrust reversing.
Other patents of interest are U.S. Pat. No. 4,482,107 granted to Metz on Nov. 13, 1984 entitled "Control Device Using Gas Jets For Guided Missile", U.S. Pat. No. 4,552,309 granted to Szuminski et al on Nov. 12, 1985 entitled "Variable Geometry Nozzles For Turbomachinery", and U.S. Pat. No. 4,805,401 granted to Thayer et al on Feb. 21, 1989 entitled "Control Vent For Diverting Exhaust Nozzle".
This invention contemplates the use of valving structure and ducting that serve to separate the fan stream and core stream when the aircraft is placed in the STOVL condition. In accordance with this invention a rotating drum having a cylindrical shell with apertures adapted to communicate with an offtake for valving the core and flow streams in the STOVL operation mode is disposed between the turbine section and afterburner of the gas turbine engine (turbo fan) of the type that includes mechanism for fully closing the exhaust nozzle. The offtake may be a twin duct or coannular configuration. The system is designed so that a portion of the fan air which is typically utilize to cool the hot components of the engine continues to maintain the cooling requirements both for the offtake structure and the engine's downstream components such as the exhaust nozzle when the aircraft is in the STOVL operating condition.